Hot-water system



March 6, 1951 L.. F. WHITNEY ET Al.

HOT-WATER SYSTEM Filed JunelQ, 1947 4 Sheets-Sheet 1 March 6, 1951 F. WHITNEY/m- AL 2,544,408

HOT-WATER SYSTEM Filed June 19, 1947 4 Sheets-Sheet 2 March 6, 1951 L. F. wHlTNEY ET AL 2,544,408

HOT-WATER SYSTEM Filed June 19, 1947 4 Sheets-Sheet 5 14a-Q je@ fig. .5.

4 Sheets-Sheet 4 HOT-WATER SYSTEM F. WHITNEY ET AL March 6, 1951 Filed June 19, 1947 patented Mar. 6,H 1951 UNITED STAT-Es PATENT OFFICE '2,544,408 L HOT-WATER,l SY STEM Lyman F. Whitney, Boston, William E. Whitney, Belmont, and Daniel F. Comstock, Lincoln,

Mass., assignors, by mesne assignments, to Statur Company, a corporation of Massachusetts Application June 179, 194,7, Serial No. 755,776 s claims. (ci. 12s-362) Y This invention relates to a hot water system associated with a substantially continuously operating hot water generator of relatively low Aheat-generating rate and its principal objects are to provide an efficient and reliable system wherein hot water may be automatically drawn lfrom the generator into a suitable storage tank when thev water in the generator reaches a predetermined temperature, and to provide a system wherein the water in the generator may be passed through thegsupply line to the storage tank so.v as to be` discharged for use only when at or above a preselected temperature, otherwise the flow of water is either arrested or directed to the bottom of the storage tank so as not to cool the hot water therein.

" A further object is to provide a system which i's of simple design, completely automaticvin op- Y eration, and relatively inexpensive to manufac- .ture and install.` .Y l Other objects will be apparent from the consideration of the following description and the vaccompanying drawings, wherein; e Figi is a side elevation showing schematically a` hot water system constructed in accordance .with the present invention'associated with aprefferred type of hot lwater generator;

Fig. 2 is an end'elevation of the vhot water generator;

` Fig. 3 is a side elevation illustrating a modified system; I

f "'fFig. 4 is an enlarged-vertical section of the pressure valvev connected'with the cold water inlet of the storage tankshown in the embodiment v.of Fig. 3;

Figs. 5 and 6 modifications.

are elevations illustrating further Fig. 7 is an elevation of a storage tank, similar Ltothat of Fig. l, but showing a dual thermof. static control for the hot Water supply line;

Figs. 8 and 9 are enlarged end and side eleva` tions of the dual control device; andy Fig. 10 issection on the line Ill-l0 of Fig. 9.

such as a large storage tank preferably capable VVwater generator over a period of eight hours or more, depending on the character of the demand, the storage tank being provided with a hot Water inlet, preferably at its upper part, a hot water discharge line, a cold water inlet and a wastedischarge port both preferably at its lower part. The hot water inlet is connected through a hot water supply line to the outlet of the hot water "generator and the cold water inlet is connected either to the same hot water supply line or to a cold water supply line, but in either case means y are provided so -that either hot or cold water may ow into the tankwhen the discharge line is open. Athermostatically-operated normally closed valve l5 this valve includes a thermostatic element such is connected with tne waste-discharge port and as a bulb containing fluid or a bimetallic element or other temperature-responsive member disposed in or otherwise associated with the hot water generator or hot water supply line so that when the water therein reaches a preselected ternperature, the thermostatic element is operative to open the waste-discharge valve, thereby to cause 'cold water to be' admitted to the generator and simultaneously pass hot water from the generator to the tank preferably through the hot water inlet. With this construction and arrangement hot Water may normally pass from the generator through the tank to the discharge line when the latter is open, but if the hot water demand on the y system should slacken or cease for any appreciable period of time, then as the generator continues to operate, thehot water therein is periodically automatically transferred to the storage tank by 4tities of Vhot water.

the operation of the thermostatically operated waste-discharge valve. Hence, the generator may be set for'itsV most eiiicient operation and'may operate continuously, if desired, without danger of overheating or undue waste of water or heating medium. Y

Suchv a system, particularly when associated with a hot water generator constituting a part of a refrigerating apparatus, may advantageously be employed in homes, restaurants and other establishments whichnot only require continuous refrigeration, but also periodically consume quan- In such installations the system may be so ,designed that suicient hot water will be generated and stored during the periods between demand to take care of the major portion, if Vnot the entire hot water demand, thereby eliminating the necessity for installing a costly hot water system adequate to satisfy the usual demands.

` pi receiving andy storing the output of thehot Referring to Figs. 1 and 2, the reference charerant return duct 34;

` hereinafter described.

acter R indicates a refrigeration apparatus of the type shown in Fig. 1 of Patent No. 2,174,302, reference numerals 32, 34, 54 and 59 respectively referring to the refrigerant vapor duct, refrigerant return duct, alcohol (or other heat-transfer fluid) pipe, and the alcohol return pipe, to which parts the same numerals are applied in the above-mentioned patent. Since the refrigerating apparatus R is substantially identical with that shown in Fig. 1 of the above-mentioned patent (exceptfor: the parts 33 and 55), reference thereto may be had for a more complete disclosure; ofthe-system; In place of the condenser'sA 33 and 35 shownin;

the above-mentioned patent, thereis providedtwo` separate condensers and |02, respectively associated with the refrigerant ducts 32, 34 and the heat-transfer fluid pipes 54, 59.y The-refrigeration apparatus R and associated condensers. |0| and |02 constitute the hot water generator which ,is the subject matter of the aforesaid copending application of Lyman F. Whitney and,V as above noted, is herein shown and described' as being illustrative of the preferred type of hot water generator.

' |`|2`is secured to the closure plate |05v alcove and to one sideof the inlet |08 and extends along and in spaced relation to the lower wall oi?Y the cylinder |05 so as to stratify the incoming Water. The refrigerant vapor duct 32' projects through the opening |01 in spacedt'elescopic relation to a return tube ||4 having a closed inner end. and.v

provided With heat dissipating ns. H5.A The duct 32 and tube ||4 are preferably inclined andthe outer end' of the tube |`|'4 extendsthrough the opening |01' and is connected'. with the,Y refrigconnecteol by a pipe ||8` with a condenser |12,l

With this construction and arrangement the refrigerant duct 32 and return tube 4 constitute the hot fluid passage ofthe condenser 'in heat exchange relation withthe cold fluid pas-V sage dened by the baille |'I2 and the interior. of

, the cylinder |05; andhence the, hot refrigerant vapor passing up throughY duct 32. into. return tube I |4 and back to return duct 34 gives up heat to the water in the cylindery |0`5 so` that. ther water is preheated'V before passing into the, condenser. |02 and the refrigerant is condensed and returned to the refrigeration` sysem at a relatively low temperature.

The condenser |02 comprises alargerxshell or cylinder |20 suitably supported abovethe cylinder |05 and is provided with a closure plate |2| having at its lower partawater inlet |22' (Fig. 2) anda heat-transfer fluid inlet |24. Theupper. part of the closure plateV is` formed with a hot water outlet |25 beneath which are two small openings for receiving the bulbs or other thermostatic elements of valvesv associated" with the supply line |28 is connectedL with the` outlet |125.

- AL baille |29, supported by the'closure plate 2| above and at one side of the inlet |22; extends along and in spaced relationto-the lower wall of?` The water outlet |094 is.v

the cylinder |20 so as to stratify the incoming preheated water from the condenser |0|.

The upper end of the heat-transfer fluid pipe 54 is connected with a coupling member |30 connected with a condenser tube |3|, constituting the hot fluid passage of thecondenser, which eX- tends through the opening l|24 into the interior of the cylinder |20 and being supported in any suitable manner preferably in an inclined position. The condenser tube |3| is provided with spaced heat-dissipating fins |32 and its inner endisconnected with an air chamber |34 which i's connected'to asmall pipe line |35 which providesa connection by means of which the circuit may be initially evacuated, as described in the aforesaid Whitney Patent No. 2,174,302.

The operation'. of the system thus far describedis as follows:

' Assuming that water. from supply line |0 lls the cylinders |05 and |20 and that the refrigeration apparatus R isl normallyv operating, the hot refrigerant vapor from the aspirator passes up through pipe 32 into the tubeV ||4c ofA the condenser |0| and the hot alcoholv vapor (or otherv heat-transfer fluid) fromv the aspirator jackets passes'up through pipe 54 into the condenser tube |3|` of the condenser |02. The

'condensing refrigerant vaportransfers heat to tl'ieY water inV the cylinder |05, thereby preheating the water therein, and likewise the condensing alcohol vapor in the tube |3|, being hot.er than the refrigerant'vapor,` transfers additional heat tothewater'in the cylinder 20. When wateris drawn ol'through supply line |28, the preheated waterin` condenser |0| passes through pipe ||8 into the cylinder |20 where it receive additional heat from the condensing alcohol in tube |3|,

' The water inthe condenser |0| effects condensation ofV the refrigerant, vapor and the condensate is returned through pipe 34 tothe evaporator trap-of the-refrigeration system.

rPhe condensedalcohol 'in' the tubev |3| isA returned through pipe 59to the interstage jacket of the aspirator. The thermostatic elements, as

' hereinafter described, operate periodically to effectthe discharge of hot water through the supply line |28 so' that'the temperature ofY the `Vwater in the cylindery |20 does not rise to the point of inefficient opera.ion of the regrigeration system: f When water is'd'rawn off through supply line |28, a corresponding amount of cold'wat'er enters the-lower condenser |0|v through the line |-'|0`and thepreheated Water from the condenser |0|1 passes into thev condenser 02 and in this way sufficient cold water enters the hotwater generator to insurek efficient operation of the refrigeration apparatus. l

' In the embodiment shown in-Figj. 1 the'supply line |28- isconnected to a' thermostatically controlled, electrically'operated two-wayA valve |40 whichf-isfalways open to' one of the'two branches, but closed-tothe other. One Vbranch is connected through high temperature supply line |4| to the inlet |-42iat the topA part ofA a storage tank T and the other branch is connected` by ak lower' temperature supply line |44 to the lower'temperature Y inlet |45 located at thelower part of the tank T.

1 denser"|02, the' bulb communicating with the operatingmechanism ofthe valve by a capillary lineV |50. The, valve. and associated partsv areso set oradjusted'thatthe valve opens to pass water through the line |.4| into the'top of thevtank T when the water in the condenser |02 is at or above the selected minimum temperature at which the system is required to deliver water, e. g., 120 to 180 F., but when below the selected minimum temperature the Valve is operated to pass water through the line |44 into the lower part of the tank.

The upper part of the tank is provided with an outlet |52 connected with a discharge line |54 and the lower part of the tank is provided with an opening |55 connected with a normally closed thermostatically operatedv waste-discharge valve |58. The valve |58 is also of the electrically actuated type and is associated with a thermostatic element or bulb |60 disposed in the other of the Y openings in the closure plate |2| of the condenser |02, the bulb being connected with the operating mechanism of the valve |58 by a capillaryline |62. The valve |58 and associated parts are so set or adjusted that the valve opens to discharge water from the bottom of the tank when the water in the condenser |02 reaches a selected temperature above which the operation of the refrigeration apparatus R becomes ineicient, which may be of the order of 170 to 210 F.

In operation hot water from they generator normally passes through the valve |40 and inlet |42 into the upper part of the tank T when the discharge line |54 is open, so long as the temperature of the water is at or above the aforesaid prescribed minimum. Should hot water be withdrawn from the tank at a rate greater than the capacity of the generator to replenish it, then the temperature of the water in the condenser |02 drops below the prescribed minimum, thereby causing the thermostatic element |48 to operate valve |40 so as to close the line |4| and pass the cooler water to the line |44 so that it enters the bottom of the tank and hence does not cool the hot water in the top of the tank. Should the demand for hot water slacken or cease, the generator, nevertheless, continues d to operate and when water in the condenser |02 reaches the prescribed temperature for operating the wastedischarge valve |58, the cool water in the bottom of the tank T is discharged and the hot water flows from the condenser |02 through valve |40, line |4| into the top of the tank T. Simultaneously cold water enters the generator from the supply line ||0, as above-described, and the temperature of the water inthe condenser v|02 drops sufciently to effect closing of the wastedischarge valve |58. This operation continues periodically so that a supply of hot water builds up in the tankT.

It will' be noted that so long as there is ho water available in the generator it is automatically passed to the upper part of the tank T, but if the water in the generator is not suiciently hot for use, it is automatically passed into the bottom of the tank. Since the tank T has a capacity suiciently great to receive the output of hot water from the generator for a period of a number of hours, an adequate supply of hot water may be built up without danger of overheating or impairing the efficiency of the associated refrigeration apparatus.

The embodiment shown in Fig. 3 is, in principle, the same as the embodiment of Fig. 1 and the same or similar reference characters are applied vto like parts. In this embodiment the thermostatically-controlled, electrically-operated valve |40a is a normally closed one-way valve, operaltive when the water in thegeneratorreaches a selected temperature to open so as to pass the hot water through inlet |42 into the upper part of the tank T, but otherwise to arrest the How of water to the top of the tank. The valve |40a is of a size suiiiciently large to prevent an appreciable drop in pressure within the tank when either line |54 or valve |58a is open.

A cold water supply line |10 is connected by a T |1| to the line ||-0 leading to the inlet |08 of the condenser |0| and to a line |44a leading to the lower temperature water inlet |45a of the tank T. A pressure valve |45 is connected in line |44a, and, as shown in Fig. 4, is provided lwith a. weighted head |14 operative normally to maintain the valve closed when the pressure in the line |44a is approximately the same as or less than that in the tank T, and to permit the valve to open so as to pass cold water from the line y|'|0 into the lower part of the tank when the pressure therein drops appreciably below that in the line |44a.

In operation hot water above a selected minimum temperature in the generator maintains the valve |40a open. When the valve |40a and the discharge line |54 are open, hot water passes into the upper part of the tank at a rate suicient to prevent a pressure drop which would cause the valve |45 to open. Likewise, when the wastedischarge valve |58a opens in response to an accumulation of excess hot water in the generator, hot water passes through the valve I40a to the upper part of the tank; but should the demand be such as to draw oi hot water from the generator so that the temperature in the condenser |02 drops below the selected minimum, then thevalve |40a closes; and when the discharge line |54 is opened, thereby causing an appreciable drop in pressure within the tank T, the valve |45 automatically operates to admit cold water from line |10 through line |44a into the lower part of the tank to replenish water drawn off through line |54. Closing the discharge line |54 reestablishes the pressure within tank T to close valve |45.

The embodiments of Figs. 5 and 6 are substantially identical to that of Fig. l, except for the two-way valve |40.v In Fig. 5 the valve |40b isa manually-operated valve and hence must be set in one of two positions. In operation the valve |40b would be set so as to divert water through the line |44 into the lower part of the. tank throughout that part of the dayduring which hot water is being used faster than it is heated by the generator, and would be set so as'to direct hot water through the line |4| into the upper part of the tank T throughout the period during which hot water is not being used.

In the embodiment of Fig. 6 the valve |40c is of the type having a self-contained thermostatically operative element eiective to open the valve to line |4| when the water flowing therethrough is at or above a selected temperature, and in all other particulars the operation is identical to that of the embodiment of Fig. 1.

Each of the above-described embodiments may, under certain conditions of operation, be wasteful of heated water. For example, if all of the hot water in the storage tank has been used and the tank is full of cold water and the water in the generator vis warm, but below the preselected minimum temperature, it would be wasteful to send this-warml water to the bottom of the storage tank where it would be unavailable for use. In order to prevent this difculty, we may use `a thermostat located in the top of the storage tank cooperating with a thermostat located either in the generator orffin' thesu'pply Aline to ftlleastorage tank so:E thattheY water from thegenerator not only passes-torthe top of "thestoragetank when itf is at or :above the preselected minimum tem'- perature, asde'scribed in theV preceding embodi# ments, but also-passes-to thel top of the storage tank whenever itis warmer' than the water in the-v topl of` the' storage tankf; otherwise it'v is diverted tothe ybottornofthe storage tank. This may be` accomplished in a` manner presently to be described.

Referringv toFigs. 'T toY 10; the storage tank T is: substantially identical to'- that of theembodiment'off'Fi'g. 1, except that' the electricallyeopera'tedtwo-wayvalve'` I 49d is associatedwithal dual control device |8Uwhich operates the'va-lve |'4Dd to pass-the incoming waterfrom the generator t'c \tlietep'ofv thetank 'Il either "when: itis at o1' above a; preselected temperature; or when itL is abovev the tem;f eratu'rev ofthe waterA in thel top of the tank T.

'I'hedevice` |80`cornprises a base-|8| whichsup@ ports av pair of bellows |86 and |85; the bellows |84 being connected by a'capillary line |86 to a bulb-|811, which may be located either in the hot water generator (as in the previously described embodiments or in the supplyline |28 adjacent tothe' valve Mild, as shown-in-Fig. 7. Thebellows |85 is connected by a capillary line |88 to a bulb |90" located in the top of the tank T. A bracket |9|l isf secured to the base- |8| and supports atresilienthorizontal-arm |92 adapted to be readily flexed both longitudinally and transversely. Mounted' on the end of the arm |92' is a cross bar or follower |94, the opposite ends of which arey held in'contact with the upper ends of the bellows by a tensionspring |95, as shown in Fig. 8'. Centrally mounted on the upper face of the follower |94is'a vertical extending arm |96 which isisupp'orted-either in a dead center or vertical po'sitiorrwhen` the bellows hold the followerin a horizontal position, or in one or two positions to the' right or left ofthe vert-icalposition, dependingiupon the position in which thebellows hold the follower. Thus, expansion-of the bellows |84 i andE |85 not onlyvariesY the level of thefollower |94f butlal'soV the position of1 the arm |95.

.Ai normally open micro-switch 2D`0is' mounted on a-.bracket 29| so that its opera'ting'arrn 292 is' engageable withvone end of thefcllow'er |94 ,l `andia normally 'open micro-switch 2941s mounted onrabracket 285 so-that its operating arm 205 vis engageablewith the' upper end portion of the arm'. |96. The switches 290 and' 294 are con'- `nested in parallelwitli each other in the control circuit for the electrically actuated valve 49d, as shown in Fig. '7.

The `construction and arrangement of partsrare such that when the water in the supply line |28 isatfor'above a preselected temperature, theY bellows |84 is-extended suiiiciently to hold'the adjacent. end of the follower |94' in its uppermost position, wherein it engages the operating arm 202,;so1as-t`oclose switch 299, and when thewater in the supply line |26 -is below thesaidpreselected temperature, the bellows |84 contracts so as to supportthe adjacent end of the follower |94 at a level below'that required to close switch 209; and. when the water in the top of the-tank T is at or above a preselected temperature (which may be the same=or somewhat less thanthe preselected temperature causing the bellows |84 to close switch 290)., the bellows |85 is extended' suflioientlyto supportthe adjacentend of thefollower lMatlitsuppermost position, in whichJ thearm |96is held" either in "dead centenfor. tofthexleft of deadV center, in either; of which positions: the switch 204i remainsopen,

It is apparent that so long. as the water.' in the line |28is at or above the preselected temperature-the bellows |84 will hold the switchlZDU closed, thereby operating valver |40d to passfhot water through the line 4| into the top of; the tank T, butyshould the temperature ofthe water passing through the line |28 drop below the preselected temperature, the bellows |84 would contract sufficientlyv to permit spring |95, to pull or tilt the adjacent end of the follower down? wardly' to` open switch 20), thereby operating valvel UmdY to pass' the cooler water through line |44 into the bottom of the. tank, provided that the. water in thetop of' tank. T is. warmer than that' passing through lineV |28. So long as-ther-water inthe tank T is at. or above the preselected'temperature, the bellows' |35;V remains extended so as to hold the arm ISS-eitherinvertical' position, or tilted toward the left in event that the bellows |84 is not fully extended,. and in both instances theswitch 264 remains open. Should the water in the tank T drop below the temperature of the water in the line |28, then the bellows |85 would contract relative to the bellows |84, thereby causing the follower |94 and arm |96 to tilt toward the right, as indicated by the dot and dash lines of Fig. 8,' so as to closeA switch. 2.84, thus operating valve |4011" to pass water'to thev top of thetank T, even though the incoming: water was below the preselected temperature. necessaryv to close switch. 209, it being'notedrtha't thel arm |96' remains operative to close switch 294 when the follower |94 is appreciably below the horizontal level necessary tooperate switch 209.

It is apparentv from the foregoing that with this system water will pass from the generator to the top of the tank T when (a) the temperature of the water coming from thelgenerator is above the desired preselected temperature, or ('b.) .when the temperature of the water coming from the generator is-'higher than the temperature of the water in the'top of the tank T, even though the water in the generator is below the preselected temperature;

VWhile we` have' shown and described different desirable embodiments of the invention', it is vto be understoodthat this disclosure is for the purpose vof illustration and that various changes and modications, as well as the substitution of equivalent elements for those herein shown and described, may be made without departing from the spirit and scope of the invention asset forth in the appended claims.

We claim.:

1. In combination with a substantially. continuously operating hot water generator having a cold water intake and hotwater outlet, a hot water system comprising a storage tank hav-ing hot water and lower. temperature water inlets andi a hot water discharge line, valve means associated with said inletsand operative toclose one inlet when the other is open, a hot water supply line connecting the hot water inlet with the hot water outlet of said generator so that hot water from said generator ows into said tank when said discharge line is open and the lower temperature water'inlet is'closed, and a thermostatically operated, normally closed,l waste-dischargevalve connectedfto said tank for discharging water therefrom, said thermostatically operatedwaste-dischargevalve-including a' thermostatic element associated with said generator and operative to open said waste discharge valve When the water in said generator reaches a selected temperature, thereby to admit cold water to said generator and simultaneously pass hot water from said generator to said tank.

2. In combination with a substantially continuously operating hot water generator having a cold water intake and hot water outlet, a hot water system comprising a storage tank having hot Water and lower temperature water inlets and a hot water discharge line, valve means associated with said inlets and operative to close one inlet when the other is open, ahot water supply line connecting the hot water inlet with 'the hot water outlet of said generator, said. supply line including a thermostatically operated valve operative only when the water passing from said generator into said supply line is above a selected temperature to pass hot water from said generator to said tank when said discharge "line is open, a water supply line connected with the lower temperature water inlet and operative to admit water to said tank when said thermostatically operated valve arrests the'flow of hot water through said hot water inlet, and a thermostatically operated waste discharge valve including a thermostatic element associated with said generator and operative to open said waste-discharge valve when the water in said generator reaches a selected temperature, thereby to admit cold water to said generator and simultaneously pass hot water from said generator tosaid tank.

3. In combination with a substantially continuously operating het water generator having a cold water intake and hot water outlet, a hot Water system comprising a storage tank having hot water and lower temperature water inlets and a hot water discharge line, a hot water supply line connected with the outlet of said generator, a two-way valve in said supply line connected with two branches, one branch being connected to the hot water inlet of said tank and the other branch being connected to the lower temperature water inlet of said tank so that when said discharge line is open water may iiow through one of said branches into said tank, and a thermostatically operated normally closed waste-discharge valve connected to said tank for discharging water therefrom, said thermostatically operated valve including a thermostatic element associated with said generator and operative to open said waste-discharge valve when y the water in said generator reaches a selected temperature, thereby to admit cold water to said generator and simultaneously pass hot water from said generator to said tank.

4. In combination with a substantially continuously operating hot water generator having a cold'water intake and hot water outlet, Ia hot water system comprising a storage tank having hot Water and lower temperature water inlets and a hot water discharge line, a hot water supply line connecting the hot water inlet with the hot water outlet of said generator, a thermostatically operated valve in said supply line having a thermostatic element associated with said generator and effective to operate the valvewhen the water in said-generator reaches a selected temperature so that hot water from said generator flows into said tank when said discharge line is open, a supply line connected with the lower temperature water inlet for admitting water to said tank when said discharge line is open and when thermostatically operated valve arrests the now of hot water to said hot water inlet, and a thermostatically operated, normally closed, waste-discharge valve connected to said tank for discharging water therefrom, said thermostatically operated waste-discharge valve including a thermostatic element associated with said generator and operative to open said waste-discharge valve when the water in said generator reaches a selected temperature, thereby to admit cold water to said generator and simultaneously pass hot water from said generator to said tank.

5. In combination with a substantially continuously operating hot water generator having a cold water intake and hot w-ater outlet, a hot Water` system comprising a storage tank having hot water and'lower temperature water inlets and a h ot water discharge line, a hot water supply line connected with the outlet of said generator, a thermostatically operated two-way valve in said supply line connected with two branches, one branch being connected with the hot water inlet of said tank so as to pass water from said generator through the hot water inlet of said tank when. the temperature of the water flowing through said supply line is above a selected temperature and the other branch being connected to the lower temperature water vinlet of said tank so as to pass water from said generator through the lower temperature water inlet of said tank when the temperature of water flowing through said supply line is below said selected temperature, and a thermostatically operated normally closed waste-discharge valve connected to said tank for discharging water therefrom, said thermostaticall'y operated' waste-discharge valvey in cluding a thermostatic element associated with said generator and operative to open said wastedischargel valve when the water in said generator reaches a selected temperature, thereby to admit cold water to said generator and simultaneously pass hot water from said generator to said tank.

6. In combination with a substantially continuously operating hot water generator having a cold water intake and hot water outlet, a hot water systemV comprising a storage tank having at its upper part a hot water inlet and a hot water discharge line and having at its lower part a lower temperature Water inlet and a waste-discharge port, a hot water supply line connected with the outlet of said generator including a thermostatically operated valve having two branches, one branch being connected with said hot water inlet and the other branch being connected with said lower temperature water inlet, said valve having a thermostatic element associated with said generator and operative to actuate said valve so as to pass water through said hot water inlet when the water in said generator` is above a selected temperature and to pass water through said lower temperature water inlet when the water in said generator is below said selected temperature, and a thermostatically operated normally closed waste-discharge valve connected to said port for discharging water therefrom, said thermostatically operated waste-discharge valve including a thermostatic element lassociated with said generator `and 'operativeto open said waste-discharge valve when the water in said generator reaches a selected temperature, thereby to admit cold water to said generator and simultaneously pass hot water from said generator to said tank.

'7. In combination with a substantially continuously operating hotwater generator having a cold Water intake and hot water outlet, a hot water fsystem .fcomprisingza .storage ztank; having at. its upper parte, hot water nletanda hot. water .discharge lineand `rat itsi lowerfpart .a1 cold .water inlet andra, .waste-discharge port,.v.a'co1d-water supply Vline having two. branches.;l the. rst. branch teingfconnected with the cold-water intake of said generator `and. the second branch being-connected with the-cold Water inletcf said 4tank,.a pressure operated ,Valve .in said second branch effective to pass coldwater through said..co1dwater.

inlet when ,the pressure of the waterinsaid tank falls appreciably below that in vsaid cold water supply-line, va hot water supply line vconnecting .the hot -wateroutlet'ofv said generator with .the

hot -water inlet-of said `tank,..a v.thermostatically.

-operated'normally Iclosed valve. insaid hot vwater .supply line. operative to opensc vas to admitwater tosaid tank when the water from said generator sabove1a.-selected-,tempe1ature,.and a normally vclosed.thermostatically operated. wasteedischarge .valve .connected with said ItWaste-discharg-e port and adapted to discharge .Waterfrom saidtankat `a rate preventing an appreciable pressiue dropin said tank, said thermostatically.operated wastedischarge. valve includingv a; thermostatic .element having: two branches, .one ybranch beingcOnneCted 4.outlet .of ,said generator `,and .including .a Valve l2 :with :said hotfwater.. inlet. and., the-.other branch lbeing vconnected with said `lower temperature waterv inlet, control means for said valve includingfthermostatic elements conjointly responsive to the temperature of the water in the .upperl part of said tank and With the temperature of .the watersupplied-from said generator to actuate .said Valve so..as .to pass water through saidliot water inletwhen the water passing through said valve isabove the temperature of the watervin the upper partof said tank and to actuate said valve to pass Water through said lower temperaf :ture water inlet When thewater passingthrough said valve is below -botha preselected temperature and the temperature of the water in theupperlpartofsaidtank, and a thermostatically operated normally closed waste-discharge valve connected to. saidport fordischarging water therefrom, said thermostatically operated waste-discharge valve including a thermostatic element .associated withsaid generator and operative vto v open said waste-discharge valve when the water in'said generator reaches a selected temperature, `thereby to admit cold water to said generator :and simultaneouslygpass hot water from ysaid generator'to said tank.

.'LYMANF. WHITNEY.

WILLIAM E. WHITNEY. DANIEL F. COMSTOCK.

VREFERENGES vCITED "The following-references are 4of vrecord inthe .UNITED vSTATES;PATENTS Number L Name Date .1,937,288 McGraw Nov. .28, 1933 2,125,842 Eggleston Aug.12, 1938 .2,207,057 Gulick s July 9, 1940 2,255,967 Collins ,Sept.`16, 1941 .2,271,449 '-Whitney Jan. 27, .19.42 

